The redesign of split gradient coils for a hybrid MR-PET
system is considered. Numerous changes in the coil design are assessed for
their performance with the aim of making the coil more robust. New design
strategies and a slackening of design constraints are also assessed for their
ability to mitigate any performance loss from making the coils more robust. A
linking annulus was found to be essential, but we enforce radial connections
for simplifying the construction. A complex relationship exists between the
design constraints and the coil performance, which needs to be considered
carefully before a final design is constructed.